Physics Letters B最新文献

{"title":"Signals of nonrenormalizable Lorentz and CPT violation at the LHC","authors":"Enrico Lunghi ,&nbsp;Nathaniel Sherrill","doi":"10.1016/j.physletb.2025.139366","DOIUrl":"10.1016/j.physletb.2025.139366","url":null,"abstract":"<div><div>We examine nonrenormalizable Lorentz- and CPT-violating effective operators applied to the quark sector of the Standard Model. Using Drell-Yan events collected by the ATLAS and CMS Collaborations, several constraints are extracted from time-independent modifications of the cross section on the <em>Z</em>-boson pole. The sensitivity to time-dependent modifications is also estimated by simulating a sidereal-time analysis. Our results suggest a dedicated search can improve on constraints from deep inelastic scattering by up to three orders in magnitude.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139366"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neutron activation as benchmark for cross section evaluations: Demonstration through the MACS of 50Cr for nuclear technology applications","authors":"P. Pérez-Maroto ,&nbsp;C. Guerrero ,&nbsp;B. Fernández ,&nbsp;A. Casanovas-Hoste ,&nbsp;M.E. Stamati","doi":"10.1016/j.physletb.2025.139360","DOIUrl":"10.1016/j.physletb.2025.139360","url":null,"abstract":"<div><div>Neutron cross section libraries often differ with each other due to the limited availability of differential cross section data from time-of-flight experiments. These are indeed challenging, requiring state-of-the-art facilities and detectors, as well as an involved data analysis. However, in some cases, an easier alternative can be found in simpler integral experiments, as it is demonstrated herein. The capture cross section of ⁵⁰Cr plays an important role in nuclear reactors and recent criticality safety benchmarks pointed to an increase of 20%, which has been incorporated in the recent INDEN (2023) evaluated library. In this work we have carried out an epithermal neutron activation measurement on ⁵⁰Cr at the CNA HiSPANoS facility. The resulting Maxwellian Average Cross Section (MACS) at 30 keV, 37.1(20) mb, provides enough evidence to discard the proposed increase in the cross section. Furthermore, it illustrates the suitability of the activation technique to benchmark cross section evaluations in the epithermal energy region. This can in principle be extended to other reactions (as far as they result in radioactive nuclei) and to the fast neutron range by employing mono-energetic beams from D-D and D-T reactions in similarly simple experiments.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139360"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determining the duration of the hadronic stage at RHIC-BES energies via resonance suppression using a full set of rate equations","authors":"Tim Neidig ,&nbsp;Apiwit Kittiratpattana ,&nbsp;Tom Reichert ,&nbsp;Amine Chabane ,&nbsp;Carsten Greiner ,&nbsp;Marcus Bleicher","doi":"10.1016/j.physletb.2025.139339","DOIUrl":"10.1016/j.physletb.2025.139339","url":null,"abstract":"<div><div>We present realistic estimates for the duration of the hadronic stage in central Au+Au reactions in the RHIC-BES energy regime. To this aim, we employ a full set of coupled rate equations to describe the time evolution of the system from chemical to kinetic freeze-out. Combined with the recently measured data by the STAR collaboration on <span><math><msup><mrow><mi>K</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>/</mo><mi>K</mi></math></span> ratios, we show that the previous estimates substantially underestimated the duration of this stage due to the omission of the regeneration of hadron resonances. We provide an improved relation between the <span><math><msup><mrow><mi>K</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>/</mo><mi>K</mi></math></span> ratio at chemical and kinetic freeze-out and the life time of the hadronic phase. The calculated improved life times are now in line with estimates from other methods and are relevant for the NA61 and STAR collaborations and for upcoming experiments at the FAIR facility.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139339"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of resonances in Gamow window for 12C+12C fusion reaction via thick-target inverse kinematics method","authors":"Weike Nan ,&nbsp;Youbao Wang ,&nbsp;Jun Su ,&nbsp;Yaode Sheng ,&nbsp;Richard James deBoer ,&nbsp;Yuqiang Zhang ,&nbsp;Luyang Song ,&nbsp;Fuqiang Cao ,&nbsp;Chen Chen ,&nbsp;Chao Dong ,&nbsp;Yunju Li ,&nbsp;Zhihong Li ,&nbsp;Gang Lian ,&nbsp;Wei Nan ,&nbsp;Yangping Shen ,&nbsp;Na Song ,&nbsp;Shengquan Yan ,&nbsp;Seng Zeng ,&nbsp;Bing Guo ,&nbsp;Weiping Liu","doi":"10.1016/j.physletb.2025.139341","DOIUrl":"10.1016/j.physletb.2025.139341","url":null,"abstract":"<div><div>The ¹²C+¹²C fusion reaction at deep subbarrier energies is important for understanding the carbon burning process in massive star and explosive binary systems. However, its reaction rates are very difficult to measure directly or evaluate by simple extrapolation due to the extremely small cross sections and complex resonance structures near the Gamow window. In this work, we use one of its exit channels, <em>i.e.</em> ²³Na+<em>p</em> to populate the excited states of the compound nucleus ²⁴Mg via the conventional thick-target inverse kinematics method. By applying <em>γ</em>-charged particle coincidence, we have obtained excitation functions for the proton and <em>α</em> emission channels, respectively, and derived the resonance parameters through a simultaneous multi-channel R-matrix analysis. It is clear that a series of discrete resonances exist in the most relevant excitation energy region of ²⁴Mg. The astrophysical <em>S</em>-factor of the ¹²C+¹²C fusion reaction is evaluated by adopting a systematic reduced width for the entrance channel. In particular, branching ratios of the dominant four decay channels are estimated across the entire Gamow window of the ¹²C+¹²C fusion reactions. Significant fluctuations are shown that may have strong impacts on the final outcome of the carbon burning process.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139341"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"(Quasi-)normal modes of rotating black holes and new solitons in Einstein-Gauss-Bonnet","authors":"Lilianne Tapia ,&nbsp;Monserrat Aguayo ,&nbsp;Andrés Anabalón ,&nbsp;Dumitru Astefanesei ,&nbsp;Nicolás Grandi ,&nbsp;Fernando Izaurieta ,&nbsp;Julio Oliva ,&nbsp;Cristian Quinzacara","doi":"10.1016/j.physletb.2025.139347","DOIUrl":"10.1016/j.physletb.2025.139347","url":null,"abstract":"<div><div>In this paper, we analyze the scalar field (quasi-)normal modes of recently derived rotating black holes within the framework of Einstein-Gauss-Bonnet theory at the Chern-Simons point in five dimensions. We also examine the mode spectrum of these probes on new static gravitational solitons. These solitons, featuring a regular center, are constructed from static black holes with gravitational hair via a double analytic continuation. By imposing ingoing boundary conditions at the horizons of rotating black holes, ensuring regularity at the soliton centers, and imposing Dirichlet boundary conditions at infinity, we obtain numerical spectra for the rotating black holes and solitons. For static black holes, we demonstrate analytically that the imaginary part of the mode frequencies is negative. Our analysis of the massless Klein-Gordon equation on five-dimensional geometries reveals an infinite family of gapped, massive three-dimensional Klein-Gordon fields, despite the presence of a non-compact extended direction. For the static solitons, the frequencies are real and non-equispaced, whereas in the rotating black holes, counter-rotating modes are absorbed more quickly, and the imaginary part of the co-rotating modes approaches zero as extremality is approached. Additionally, we show that both the rotating black holes and solitons can be equipped with non-trivial torsion, leading to a novel branch of solutions.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139347"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Signature of 0+ excited state and shape coexistence in 94Kr through 93Kr(d,p)94Kr reaction","authors":"D. Walter ,&nbsp;R. Kanungo ,&nbsp;M. Holl ,&nbsp;S. Roy-Garand ,&nbsp;B.S. Hu ,&nbsp;J.D. Holt ,&nbsp;M. Alcorta ,&nbsp;C. Andreoiu ,&nbsp;S. Bhattacharjee ,&nbsp;A.A. Chen ,&nbsp;A. Chester ,&nbsp;D. Connolly ,&nbsp;B. Davids ,&nbsp;N. Esker ,&nbsp;F. Garcia ,&nbsp;S. Gillespie ,&nbsp;G. Hackman ,&nbsp;S. Ishimoto ,&nbsp;R. Krücken ,&nbsp;P. Jassal ,&nbsp;C. Waterfield","doi":"10.1016/j.physletb.2025.139352","DOIUrl":"10.1016/j.physletb.2025.139352","url":null,"abstract":"<div><div>A measurement of the excitation spectrum of ⁹⁴Kr via one-neutron transfer to the ground state of ⁹³Kr using the ⁹³Kr(<em>d,p</em>)⁹⁴Kr reaction at 8<em>A</em> MeV, observing the outgoing protons, performed with the IRIS facility at TRIUMF is reported. Two states in ⁹⁴Kr, at 1.50±0.14 MeV and 2.20±0.14 MeV, were observed. An adiabatic-wave approximation analysis of the differential cross sections leads us to identify the lower energy state as being populated with neutron transfer to the 3<span><math><msub><mrow><mi>s</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> orbital. This leads to the first observation of the lowest 0⁺ excited state in ⁹⁴Kr, hence signaling shape co-existence. Theoretical calculations performed within the in-medium similarity renormalization group framework are presented that also show the existence of a low-energy 0⁺ state, aligning qualitatively with the observation.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139352"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmological implications of f(R,Σ,T) gravity: A unified approach using OHD and SN ia data","authors":"N. Myrzakulov ,&nbsp;S.H. Shekh ,&nbsp;Anirudh Pradhan","doi":"10.1016/j.physletb.2025.139369","DOIUrl":"10.1016/j.physletb.2025.139369","url":null,"abstract":"<div><div>This paper investigates the cosmological implications of the modified gravity framework known as <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>Σ</mi><mo>,</mo><mi>T</mi><mo>)</mo></math></span> gravity, focusing on its potential to unify and extend current cosmological models. The theory, introduced by Bakry and Ibraheem in 2023, combines the Ricci scalar, a scalar parameter representing torsion or other geometric properties, and the trace of the energy-momentum tensor. By analyzing observational Hubble data (OHD) and the Pantheon compilation of Type Ia Supernovae (SN Ia), we explore how this framework provides the accelerated expansion of the universe, the nature of dark energy, and phenomena like the Big Rip singularity. Employing the Friedmann-Robertson-Walker (FRW) metric and solving the modified field equations, we derive key cosmological parameters such as the Hubble constant and matter energy density parameter. These parameters are constrained through statistical analysis of observational data, yielding and from OHD, and from SN Ia. The evolution of the equation of state (EoS) parameter, isotropic pressure, and energy density is also investigated. By considering energy conditions and stability criteria, the study highlights the viability of gravity as an alternative framework to General Relativity and models. Our findings affirm the model's compatibility with current observational evidence and its potential to the universe's past and future dynamics.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139369"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143547971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of spin-density matrix elements in Δ++(1232) photoproduction","authors":"","doi":"10.1016/j.physletb.2025.139368","DOIUrl":"10.1016/j.physletb.2025.139368","url":null,"abstract":"<div><div>We measure the spin-density matrix elements (SDMEs) of the <span><math><msup><mrow><mi>Δ</mi></mrow><mrow><mo>+</mo><mo>+</mo></mrow></msup><mo>(</mo><mn>1232</mn><mo>)</mo></math></span> in the photoproduction reaction <span><math><mi>γ</mi><mi>p</mi><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>Δ</mi></mrow><mrow><mo>+</mo><mo>+</mo></mrow></msup><mo>(</mo><mn>1232</mn><mo>)</mo></math></span> with the GlueX experiment in Hall D at Jefferson Lab. The measurement uses a linearly–polarized photon beam with energies from 8.2 to 8.8 GeV and the statistical precision of the SDMEs exceeds the previous measurement by three orders of magnitude for the momentum transfer squared region below 1.4 GeV². The data are sensitive to the previously undetermined relative sign between couplings in existing Regge-exchange models. Linear combinations of the extracted SDMEs allow for a decomposition into natural and unnatural–exchange amplitudes. We find that the unnatural exchange plays an important role in the low momentum transfer region.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"863 ","pages":"Article 139368"},"PeriodicalIF":4.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Universal laws for nuclear contacts","authors":"Tongqi Liang ,&nbsp;Dong Bai ,&nbsp;Zhongzhou Ren","doi":"10.1016/j.physletb.2025.139351","DOIUrl":"10.1016/j.physletb.2025.139351","url":null,"abstract":"<div><div>The nuclear contact characterizes the nucleon-nucleon pairs in close proximity and serves as an important tool for studying the short-range correlations (SRCs) within atomic nuclei. While they have been extracted for selected nuclei, the investigation of their behavior across the nuclear chart remains limited. Very recently, Yankovich, Pazy, and Barnea have proposed a set of universal laws (YPB laws) to describe the correlation between nuclear contacts and nuclear radii and tested their laws for a small number of nuclei by using the Woods-Saxon mean-field model Yankovich et al. (2021) <span><span>[32]</span></span>. In this Letter, we extend their study to a majority part of the nuclear chart within the framework of the Skyrme Hartree-Fock-Bogolyubov model, which incorporates several essential beyond-mean-field features and offers a more accurate description of the bulk properties of atomic nuclei. Our results suggest that the YPB laws hold as a good approximation for different nuclear mass regions, with minor deviations attributed to, e.g., isospin-breaking effects. Our work lays a firm foundation for future applications of the YPB laws in finite nuclei and provides new evidence for the long-range nature of the relative abundance of short-range pairs.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"863 ","pages":"Article 139351"},"PeriodicalIF":4.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of the neutron total cross section of Iron at the Back-n white neutron source of CSNS","authors":"Jiangbo Bai ,&nbsp;Jingyu Tang ,&nbsp;Liqun Shi ,&nbsp;Yonghao Chen ,&nbsp;Han Yi ,&nbsp;Guohui Zhang ,&nbsp;Haofan Bai ,&nbsp;Jie Bao ,&nbsp;Ping Cao ,&nbsp;Zhen Chen ,&nbsp;Zengqi Cui ,&nbsp;Anchuan Fan ,&nbsp;Ruirui Fan ,&nbsp;Changqing Feng ,&nbsp;Fanzhen Feng ,&nbsp;Keqing Gao ,&nbsp;MinHao Gu ,&nbsp;Changcai Han ,&nbsp;Guozhu He ,&nbsp;Yongcheng He ,&nbsp;Kejun Zhu","doi":"10.1016/j.physletb.2025.139355","DOIUrl":"10.1016/j.physletb.2025.139355","url":null,"abstract":"<div><div>The neutron total cross section of iron (^natFe) plays an important role in the basic science of nuclear physics, nuclear technology and nuclear energy application. A new measurement of the total cross section of iron from 0.3 eV to 150 MeV was carried out in single and double bunch modes by transmission method and time of flight method with multi-cell fast fission ionization chamber (FIC) with ²³⁵U and ²³⁸U coating materials at the China Spallation Neutron Source (CSNS). Normalized fission counts-neutron energy spectra for sample-in and sample-out states were obtained and superimposed. The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV. The transmissions obtained in single bunch and unfolded in double bunch coincided well. From 0.3 eV to 150 MeV, the ratio of most energy points of cross section in single bunch and in double bunch fluctuates within 10 %. In the energy range of 0.3 eV to 10 keV, the experimental results using 20 mm and 40 mm thickness iron samples both agree very well with the evaluated data of JEFF-3.3 and ENDF/B-VIII.0 at most energy points, fluctuating within 3 %. In the energy range of 10 keV to 150 MeV, the results agree well with the evaluated data in terms of values and trends. The main resonance peaks of the total cross section of iron at the energies of 3.94 keV, 6.24 keV, 7.76 keV, 27.9 keV, 52.1 keV, 74.1 keV, 83.9 keV, 141 keV, 170 keV, 188 keV and 386 keV are well represented in our results. The relative uncertainties of the total cross sections using the 40 mm iron sample by FIC-²³⁵U are within 2 % at most energy points. In 1.5 MeV-140 MeV region, the relative uncertainties of the total cross section using the 20 mm iron and 40 mm iron samples by FIC-²³⁸U are around 2 % and 1 %, respectively. The total cross section results can be used as a reference for nuclear data evaluation.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"863 ","pages":"Article 139355"},"PeriodicalIF":4.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}